A dated map whose keys are ordered. A dated sorted map is a dated
map whose iterator returns the mappings in order, where the order is
defined either by the keys' natural ordering or by a Comparator object.

This interface is based on the interface java.util.SortedMap.
It does not extend java.util.SortedMap directly, however,
because at least one date is needed. To make a dated sorted map appear
like a non-dated sorted map, use Adapters.asSortedMap(DatedSortedMap,D).
Similarly, to treat a non-dated map as dated, use
Adapters.asDatedSortedMap(SortedMap,D,D).

headMap

Returns a view of this dated map of all mappings whose keys precede toKey.
The key toKey does not have to appear in this dated map nor will it
ever appear in the returned map. The returned map is a fully functional
dated sorted map that is tied to this map. Changes to either will be reflected
in the other. Any attempt to add a key greater than or equal to toKey will
throw an IllegalArgumentException.

Parameters:

toKey - upper bound of the keys of the returned map (exclusive)

Returns:

the front portion of this ordered dated map up to, but not including, the
specified key

subMap

Returns a view of this dated map of all mappings whose keys fall between
fromKey (inclusive) and toKey (exclusive).
Neither key has to appear in this dated map. The returned map is a fully functional
dated sorted map that is closely tied to this map. Changes to either
will be reflected in the other. Any attempt to add a key outside the
specified key range will throw an IllegalArgumentException.

Parameters:

fromKey - lower bound of the keys of the returned map (inclusive)

toKey - upper bound of the keys of the returned map (exclusive)

Returns:

the middle portion of this ordered dated map from fromKey
(inclusive) to toKey (exclusive)

tailMap

Returns a view of this dated map of all mappings whose keys are greater
than or equal to fromKey. The key fromKey does not have to appear
in this dated map. The returned map is a fully functional dated sorted
map that is closely tied to this map. Changes to either will be reflected
in the other. Any attempt to add a key less than fromKey will
throw an IllegalArgumentException.

Parameters:

fromKey - lower bound of the keys of the returned map (inclusive)

Returns:

the back portion of this ordered dated map starting from the
specified key